I. Technical Field
The present invention relates to an electron emitting device, a display apparatus using the electron emitting device, and a method of manufacturing the electron emitting device.
II. Description of the Related Art
Display apparatuses, such as a flat panel display, using an electron emitting device realize bright image display with high contrast by emitting electrons from an electron emitting source into a vacuum and smashing the electrons against a fluorescent material to cause light emission.
In a conventional Spindt-type electron emitting device, a conical electron gun and a gate electrode having an opening at the position of the tip of the electron gun are formed over a substrate and electrons are emitted from the tip of the electron gun toward a collector electrode. Since the electron gun has a three-dimensional structure, the manufacturing process thereof is complicated, and thus the device is difficult to miniaturize.
On the other hand, in an electron emitting device of a surface emitting type, a semiconductor layer, an insulating layer, and an upper electrode are stacked over a lower electrode and a voltage is applied between the electrodes to emit electrons from the surface of the upper electrode. Although a device of the surface emitting type is easily formed in a miniature structure due to the stacked structure, thinning the insulating layer for providing high power at a low voltage may produce a defect, such as a pinhole.
To address this, Published Japanese Translation No. 2005-512280 of PCT International Publication has described a device of an MIS (Metal Insulator Semiconductor) structure formed of metal, insulator, and semiconductor in which a semiconductor layer is made of an amorphous material and an island region is provided where an insulating layer is gradually thinned. A carbon layer is formed over, under, or inside the island region, and a crystal region is provided in an electron supply layer at or near a region in which the island region has the smallest thickness. With the structure, the island region serves as an emission site and the amount of electrons emitted from the island region is increased. Since the amount of emitted electrons can be maintained even when the insulating layer has a certain thickness except the island region, it is possible to prevent a defect such as a pinhole in the insulating layer.